The survey of Japan Electronics and Information Technology Industries Association (JEITA) says that an average time spent watching television (TV) a day is 4.5 hours. However, it is known that there are changes in lifestyles occurring recently, and that the 4.5 hours is not necessarily spent continuously watching TV.
For example, when a viewer watches TV while getting ready to go to work or school in the morning or while eating, he/she does not continuously watch a screen of the TV, may turn his/her glance or talk with another person when a program such as a weather forecast, for which input from the sound is sufficient, is broadcast. Thus, interesting keywords broadcast in the current news or sports news are taken as cues, upon which behavior of watching the screen of the TV again is frequent.
That is, a typical mode of watching TV involves merely turning the TV on in place of a clock in the morning, or hearing the sound of the TV at night while operating a personal computer (PC), and so-called “half watching” is increased. When this “half watching” is carried out, power is unnecessarily consumed in the state where the screen of the TV is turned on. As such, in the related art, to reduce power consumption, TVs have a mode of turning off the screen and continuing to play back only the audio.